1. Technical Field
The present invention relates to gas filling apparatuses, and more particularly, to a gas filling apparatus for filling a gas into a storage apparatus that is used for storing a semiconductor element or a reticle.
2. Description of Related Art
In the rapidly developing semiconductor technology, optical lithography plays an important role and wherever pattern definition is conducted, optical lithography is requisite. As to the application of optical lithography relating to semiconductors, a designed circuit pattern is used to produce a light-transparent reticle with a particular shape. Basing on the principle of exposure, after a light passes through the reticle to project on a silicon wafer, the circuit pattern formed on the reticle can be exposed onto the silicon wafer. Since any dust (such as particles, powders or an organic matter) can adversely affect the quality of such projected pattern, the reticle used to produce the pattern on the silicon wafers is required with absolute cleanness. Thus, clean rooms are typically employed in general wafer processes for preventing particles in the air from defiling reticles and wafers. However, absolute dustless environment is inaccessible even in the known clean rooms.
Hence, reticle storage apparatuses that facilitate protecting reticles from defilement are implemented in current semiconductor processes for the purpose of storage and transportation of reticles so as to ensure cleanness of the reticles. When such reticle storage apparatuses accommodate reticles in semiconductor processes, the reticles can be isolated from the atmosphere when being transferred and conveyed between stations, so as to be secured from defilement caused by impurities that induces deterioration. Further, in advanced semiconductor factories, the cleanliness of the storage apparatuses is required to meet the Standard Mechanical Interface (SMIF), namely superior to Class 1. One solution for achieving the required cleanliness is to fill gas into the storage apparatuses. In the known technology, an external gas filling apparatus is connected with the storage apparatus so as to allow a gas to be filled into the storage apparatus through the gas filling apparatus.
However, in the conventional gas filling apparatus, a straight air route is typically adopted, as shown in FIG. 7. In other words, the gas in the air feed source route is a prolongated integral from the air feed source to the endmost gas outlet. Consequently, at the gas outlet nearest the air feed source, the strongest gas pressure causes the maximum gas flow rate, while at the endmost gas outlet, the decreased gas flow performs the gas pressure inferior to that at the foremost gas outlet. Such conventional gas filling apparatus is disadvantageous by the excessive gas pressure at the front gas outlets causing an excessive gas flow to be filled into the storage apparatuses that brings the risk of damaging the reticle or semiconductor elements in the storage apparatuses and the poor gas flow in company with the poor gas pressure at the rear gas outlets that possibly renders insufficient gas filling or even failed gas filling. As a result, though the storage apparatuses are attached to the identical gas filling apparatus, the undesired gas pressure distribution causes irregular and unmanageable gas flows for the respective storage apparatuses and therefore results in increased manufacturing and managing costs. Hence, it would be an important task for the industry to equalize the flows of the gas filled into each storage apparatus.
Seeing that, the inventor of the present invention provides a gas filling apparatus to improve the current technology.